Method and apparatus for fabricating unidirectional materials for helicopter parts

Abstract

A unidirectional material for helicopter parts is fabricated by winding a composite-material roving delivered from a feeding mechanism of a filament winding device around and between a plurality of pins provided on a mandrel rotating about the longitudinal axis thereof, the roving feeding mechanism being moved in a traversing manner such that the feeding path of the roving becomes a figure eight figure, whereby the roving is thus wound to form a tubular mesh of obliquely crossing and staggered helixes of the roving around the mandrel. The material has an improved strength in a transverse direction of the mandrel.

What is claimed is: 
     
       1. An apparatus for fabricating a unidirectional material, including a mandrel having two ends, drive means for rotating said mandrel around a longitudinal axis of said mandrel, roving feeding mechanism for feeding a composite-material roving so as to be wound on said mandrel, moving means for moving said moving feeding mechanism such that said roving traverses in a figure eight between said two ends of said mandrel while said mandrel is rotated, the apparatus comprising: first pin means disposed at one end of said mandrel; and   a second pin means disposed at the opposite end of said mandrel;   each of said first and second pin means having opposite end portions projecting outwardly from a periphery of said mandrel in a single transverse imaginary plane to said longitudinal axis of said mandrel, each of said first and second pin means comprising two sets of pins, said pins of each set being disposed in parallel, one set of pins projecting in one direction in said single transverse imaginary plane, the other set of pins projecting in the opposite direction,   whereby said roving is successively and alternately wound over and between said first and second pin means so as to form said unidirectional material in a tubular mesh on said mandrel and in loops around said first and second pin means.   
     
     
       2. The apparatus according to claim 1, wherein said set is a pair. 
     
     
       3. The apparatus according to claim 1, wherein said mandrel is of circular cross-sectional shape. 
     
     
       4. The apparatus according to claim 1, wherein said mandrel is a partial airfoil shape in cross section. 
     
     
       5. A method for fabricating a unidirectional material, comprising a mandrel having two ends, roving feeding mechanism for feeding a composite-material roving, the method comprising the steps of: providing a first pin assembly disposed at one end of said mandrel and a second pin assembly disposed at the opposite end of said mandrel, each of said first and second pin assemblies having end portions projecting outwardly from a periphery of said mandrel in a single imaginary plane to said longitudinal axis of said mandrel, each of said first and second pin assemblies comprising two sets of pins, said pins of each set being disposed in parallel, one set of pins projecting in one direction in said single transverse imaginary plane, the other set of pins projecting in the opposite direction;   rotating said mandrel around a longitudinal axis of said mandrel; and   winding said roving, successively and alternately, over and between said first and second pin assemblies in a figure eight so as to form said unidirectional material in a tubular mesh on said mandrel and in loops around said first and second pin assemblies.   
     
     
       6. The method according to claim 5, wherein said winding step further comprises the successive steps of: engaging said roving around an end portion of a pin of a set of said first pin assembly;   engaging said roving around an end portion of a pin of a set of said second pin assembly;   engaging said roving around an end portion of a pin of the other set of said first pin assembly; and   engaging said roving around an end portion of a pin of the other set of said second pin assembly.